It is impossible to determine the exact combat strength of any Union army at this period of the war. The army returns list all personnel ‘present for duty’, including the sick, teamsters, sutlers and cooks. Thus Grant’s Army of the Tennessee had a ‘present for duty’ strength of 48,894, but as many as 12,000 of this number may have been non-combatants. Buell stated that he brought 25,000 reinforcements to Grant’s aid, but his actual strength was 17,918. The total ‘present for duty’ strength of the two Union armies was 66,812 officers and men and 170 guns (Grant 134 guns, and Buell, 36).